The present invention relates in general to extensible vehicle trailers which can be lengthened and shortened to accommodate the trailer bed to the length of loads of different lengths, and more particularly to telescopically extensible vehicle trailers having a floating safety lock bar extending transversely between and carried by longitudinal beams of one of the extensible trailer sections and cooperative with stops at front and rear limit positions on the other trailer section to avoid accidental separation of the trailer sections if the locking device is not properly operated, and to an extensible trailer construction having support mechanism for a coiled electrical cable and air hose system arranged to avoid long unsupported spans of hoses and cables.
In recent years, a large number of vehicle trailers have been designed in such a manner that the trailers can be lengthened and shortened to accommodate the trailer bed to various load lengths or to comply with load capacity or length or wheel base requirements of various States. These extensible vehicle trailers have come into popular use because of their ready adaptability to be varied in length to meet different load carrying requirements and their ability to permit variation of weight distribution in a manner to comply with different wheel base or loading requirements of different States. Examples of such trailers are disclosed in my earlier U.S. Pat. No. 3,239,724 issued Mar. 8, 1966 and No. 3,443,822, issued Mar. 13, 1969. Those extensible vehicle trailers employ roller mounted telescopic sections making up the trailer bed, formed of a pair of longitudinal main beams on one of the sections paralleling and disposed alongside a companion pair of longitudinal main beam members of the other trailer section, together with a system of rollers bearing against the top main beam flanges of the rear section and the bottom main beam flanges of the front section. A locking mechanism is provided to hold the telescopically extensible sections in selected extended or contracted positions or at a plurality of predetermined intermediate positions between the limit positions to provide a trailer bed of desired length. This enables the operator to comply with varying local regulations concerning trailer lengths and trailer loads, and to haul long material while having the handling advantage of a short trailer for short material hauling and for empty return trips.
A problem which has been encountered in connection with such telescopically extensible vehicle trailers is that in some cases, the driver does not position the locking device properly after setting the trailer to the desired length, with the result that the two trailer sections may separate entirely from each other when the driver begins to pull the trailer along the roadway. While the telescopically extensible vehicle trailers are customarily provided with locking bolt members in the longitudinal main beams of one of the relatively movable trailer sections controlled by a linkage mechanism and operating rod to be extended into any of a plurality of locking openings in the outwardly adjacent main beams of the companion trailer section, the locking rod and linkage mechanism is not always properly secured in a position maintaining the locking bolts in projected locking position, so that the hazard of the trailer components separating from each other during operation has occurred with undesirable frequency.
An object of the present invention, therefore, is the provision of a telescopically extensible vehicle trailer of the type having longitudinal main beams of one of the trailer sections outwardly adjacent and paralleling longitudinal main beams of the companion section, wherein a floating safety lock bar is carried by the longitudinal main beam of one of the extensible trailer sections to coact with portions of the other trailer section to limit the extent of longitudinal extension or contraction of the trailer and eliminate the hazard of accidental trailer separation if the locking device for locking the trailer at a plurality of different trailer length adjustments fails.
Another object of the present invention is the provision of a telescopically extensible vehicle trailer having a manually operable locking device for adjusting the trailer to a plurality of different trailer lengths and having in addition thereto a safety locking bar which floats free in the main beams of one of the trailer sections at a predetermined position and is captured between the main beams of the companion extensible trailer section together with stops at front and rear limit positions to engage the safety lock bar and prevent relative longitudinal movement of the two trailer sections beyond the maximum and minimum trailer length positions.
Another problem which has been encountered and presents significant problems in connection with extensible vehicle trailers is the provision of proper support for the electrical cables for the light system and the air hoses for the brake system, where the length of the trailer is adjustable to different trailer lengths usually covering a range of different lengths, for example involving adjustment ranges of at least 20 feet. It will be apparent upon consideration of this problem that an extensible vehicle trailer which is capable of being adjusted to a length of 20 feet or more greater than its length in the minimum or contracted position creates significant problems in preventing unacceptable or undesirable sagging of cables and hoses at the minimum length condition of the trailer if they are to be also capable of reaching the rear end of the trailer or the rear wheel assemblies when the trailer is in the fully extended position.
Another object of the present invention is the provision of a novel supporting system for coiled electrical cables and air hoses for the light and brake systems of telescopically extensible trailers, wherein the hoses and cables are supported at or very close to their normal suspended positions below the trailer beams over the full range of extension and contraction of the trailer length.
Another object of the present invention is the provision of a support system for the coiled air hoses and electrical cables for the light and brake systems of a telescopically extensible vehicle trailer, wherein the coiled air hoses and electrical cables are coiled about flexible resilient support cords and extend between swivel mounts at opposite sides of the trailer respectively secured to the two relatively extensible trailer sections to transversely span the trailer and shift during extension or contraction of the trailer from a position inclined forwardly toward one side of the trailer at about 45.degree. to the center longitudinal axis of the trailer to a position inclined rearwardly toward that side at a similar angle to that center axis permitting the hoses and cables to accommodate to different lengths of the trailer while changing the length of the coiled cables and hoses by only a small fraction of the change in length adjustment of the trailer.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.